U.S. patent application number 13/468141 was filed with the patent office on 2013-11-14 for high intensity ultrasound for pipeline obstruction remediation.
This patent application is currently assigned to Siemens Corporation. The applicant listed for this patent is Stephen R. Barnes, Theodore James Mallinson, Thomas O'Donnell. Invention is credited to Stephen R. Barnes, Theodore James Mallinson, Thomas O'Donnell.
Application Number | 20130298937 13/468141 |
Document ID | / |
Family ID | 48468834 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130298937 |
Kind Code |
A1 |
O'Donnell; Thomas ; et
al. |
November 14, 2013 |
HIGH INTENSITY ULTRASOUND FOR PIPELINE OBSTRUCTION REMEDIATION
Abstract
High intensity ultrasound is used for pipeline obstruction
remediation. Ultrasound transducers are positioned around an
outside of the pipeline. The transducers transmit acoustic energy
into the obstruction. The acoustic energy heats the obstruction at
a location spaced away from the walls of the pipeline. As the
obstruction heats, an opening may be formed in the obstruction,
relieving pressure build-up without releasing the plug.
Inventors: |
O'Donnell; Thomas; (New
York, NY) ; Barnes; Stephen R.; (Bellevue, WA)
; Mallinson; Theodore James; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
O'Donnell; Thomas
Barnes; Stephen R.
Mallinson; Theodore James |
New York
Bellevue
Houston |
NY
WA
TX |
US
US
US |
|
|
Assignee: |
Siemens Corporation
Iselin
NJ
|
Family ID: |
48468834 |
Appl. No.: |
13/468141 |
Filed: |
May 10, 2012 |
Current U.S.
Class: |
134/1 ;
15/246 |
Current CPC
Class: |
E03F 9/00 20130101; G01N
2291/106 20130101; G01N 29/262 20130101; B08B 9/027 20130101; G01N
29/043 20130101; G01N 29/069 20130101; E03C 1/30 20130101 |
Class at
Publication: |
134/1 ;
15/246 |
International
Class: |
B08B 9/027 20060101
B08B009/027; B08B 7/02 20060101 B08B007/02 |
Claims
1. A method for use of ultrasound in pipeline obstruction
remediation, the method comprising: scanning the pipeline with
ultrasound; detecting the obstruction from the scanning;
transmitting, in response to the detecting, acoustic energy into
the pipeline from a plurality of ultrasound transducers positioned
around at least a portion of the pipeline; and directing the
transmitting of the acoustic energy focused at a portion of the
obstruction away from walls of the pipeline.
2. The method of claim 1 wherein the ultrasound transducers each
comprise an array of elements, wherein transmitting comprises
transmitting from each of the arrays of elements, and wherein
directing comprises causing a greater intensity of the acoustic
energy at the portion than spaced away from the portion due to the
acoustic energy from the arrays constructively summing at the
portion.
3. The method of claim 1 wherein directing comprises electronically
focusing the acoustic energy at the portion.
4. The method of claim 1 wherein transmitting comprises
transmitting the acoustic energy from outside the pipeline; and
further comprising: opening an aperture in the obstruction from
heat caused by the acoustic energy at the portion.
5. The method of claim 1 further comprising positioning the
ultrasound transducers spaced around at least 150 degrees of the
pipeline.
6. The method of claim 1 further comprising repeating the
transmitting and the directing for other portions of the
obstruction.
7. The method of claim 1 wherein scanning comprises scanning with
different ultrasound transducers than used for the transmitting,
the ultrasound transducers for transmitting and the ultrasound
transducers for scanning being interleaved around an outside of the
pipeline.
8. The method of claim 1 wherein detecting comprises measuring a
flow in the pipeline.
9. The method of claim 1 wherein detecting comprises identifying a
morphology of the obstruction.
10. The method of claim 1 wherein detecting comprise detecting
locations of the obstruction from the scanning, and wherein
directing comprises directing the acoustic energy as a function of
the locations.
11-18. (canceled)
19. A method for use of ultrasound in pipeline obstruction
remediation, the method comprising: transmitting acoustic energy
from a plurality of locations outside of the pipeline, the
locations spaced apart around part of a periphery of the pipeline;
and heating a portion of the obstruction with the acoustic energy
more than any heating of the obstruction adjacent to the pipeline
with the acoustic energy, the acoustic energy traveling from
different directions to constructively combine at the portion with
less combination adjacent to the pipeline.
20. The method of claim 19 wherein transmitting comprises focusing
the acoustic energy from each of a plurality of arrays, each of the
locations being at each of the arrays, the focusing being at the
portion.
21. The method of claim 19 further comprising detecting the
obstruction with ultrasound from outside the pipeline, wherein the
portion is identified from the detecting.
Description
BACKGROUND
[0001] The present invention relates to pipeline obstruction
remediation. Hydrates and waxes accumulate in pipelines, often
plugging the pipelines. The plug may cause a pressure build-up,
arrival pressure fluctuations, unexpected flow behavior (slugging),
or uncontrolled release of the plug material. Any of these events
may overload the process and instrumentation systems and lead to a
flaring event. In some cases, a rupture or other catastrophic
failure of production equipment results.
[0002] To assure flow, the accumulation of hydrates and waxes may
be alleviated. One approach is to apply heat to the exterior of the
pipeline. The outer surface of the obstruction melts first. Once
loosened, the remaining plug may be propelled by the pressure built
up behind the plug. The plug travels at high speed along the
pipeline. This may result in significant damage to the pipeline and
associated equipment.
BRIEF SUMMARY
[0003] By way of introduction, the preferred embodiments described
below include methods, systems, computer readable media, and
instructions for pipeline obstruction remediation with high
intensity ultrasound. Ultrasound transducers are positioned around
an outside of the pipeline. The transducers transmit acoustic
energy into the obstruction. The acoustic energy heats the
obstruction at a location spaced away from the walls of the
pipeline. As the obstruction heats, an opening may be formed in the
obstruction, relieving pressure build-up without releasing the
plug.
[0004] In a first aspect, a method is provided for high intensity
ultrasound in pipeline obstruction remediation. The pipeline is
scanned with ultrasound. The obstruction is detected from the
scanning. In response to the detecting, acoustic energy is
transmitted into the pipeline from a plurality of ultrasound
transducers positioned around at least a portion of the pipeline.
The transmission of the acoustic energy is directed to a portion of
the obstruction away from walls of the pipeline
[0005] In a second aspect, a system is provided for high intensity
ultrasound in pipeline obstruction remediation. At least one
ablation transducer is operable to transmit high intensity focused
ultrasound. At least one detection transducer is operable to
transmit acoustic energy for imaging. A transmit beamformer is
configured to transmit the high intensity focused ultrasound from
the at least one ablation transducer. A processor is operable to
identify the pipeline obstruction with the detection transducer and
to cause the transmit beamformer, with the at least one ablation
transducer, to transmit the high intensity focused ultrasound from
the at least one ablation transducer and at the obstruction.
[0006] In a third aspect, a method is provided for high intensity
ultrasound in pipeline obstruction remediation. Acoustic energy is
transmitted from a plurality of locations outside of the pipeline.
The locations are spaced apart around part of a periphery of the
pipeline. A portion of the obstruction is heated with the acoustic
energy more than heating of the obstruction adjacent to the
pipeline with the acoustic energy. The acoustic energy travels from
different directions to constructively combine at the portion with
less combination adjacent to the pipeline.
[0007] The present invention is defined by the following claims,
and nothing in this section should be taken as a limitation on
those claims. Further aspects and advantages of the invention are
discussed below in conjunction with the preferred embodiments and
may be later claimed independently or in combination.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The components and the figures are not necessarily to scale,
emphasis instead being placed upon illustrating the principles of
the invention. Moreover, in the figures, like reference numerals
designate corresponding parts throughout the different views.
[0009] FIG. 1 is a block diagram of one embodiment of a system for
high intensity ultrasound in pipeline obstruction remediation;
[0010] FIG. 2 is a perspective view of a cuff transducer
arrangement for ultrasound imaging and high intensity focused
ultrasound remediation according to one embodiment;
[0011] FIG. 3 is a cross-sectional view of an example of a pipeline
and a cuff of transducers; and
[0012] FIG. 4 is a flow chart diagram of one embodiment of a method
for high intensity ultrasound in pipeline obstruction
remediation.
DETAILED DESCRIPTION OF THE DRAWINGS AND PRESENTLY PREFERRED
EMBODIMENTS
[0013] An obstruction in a pipeline is detected through ultrasound
imaging, as well as remediated through high intensity ultrasound
ablation. In one embodiment, a bandolier of ultrasound transducers
surrounds the pipe. These transducers provide a visual confirmation
of the obstruction by performing tomography to reconstruct the
morphology of the plug and/or measure the flow through the pipe via
Doppler ultrasound. Once detected, a conformal approach may be
employed for ablation. The ultrasound transducers focus high
intensity energy on the same point in the interior of the pipe,
warming the plug while sparing the surrounding regions from the
same degree of exposure. Cavitations and/or displacement caused by
the acoustic energy may be used instead of or in addition to
heating. The interior portions of the plug melt first, increasing
the flow and decreasing pent up pressure. The entire plug may
dissipate and equipment downstream spared.
[0014] Through locating an obstruction using a non-invasive
ultrasound, the operational disruption of an inspection pig
operation may be avoided. In the case of hydrate and paraffin
plug/accretion removal, use of the high intensity focused is a
gentle approach which reincorporates the blockage material
progressively into the flow stream, rather than the abrupt release
of material.
[0015] Oil, gas, or other fluids or gases are transported by flow
through a pipeline. The pipeline may be made of steel, ductile
iron, or other metal. The exterior of the pipeline may be coated in
insulation material. Any size pipeline may be used, such as eight
inch to three foot inner or outer diameters. Pipelines are used on
land, underwater (e.g., subsea), in cold climates, in hot climates,
and in temperate climates. For example, the pipeline is deployed in
a high pressure, deep sea environment. The pipeline may include
joints, turns or bends, valves, or other structures.
[0016] A plug may form at various locations along the pipeline.
Plugs may repetitively form at a same location due to local
conditions. Plugs are formed of gradual deposits of paraffin (e.g.,
wax), asphalt, methane hydrate, or other materials. The build of
these materials may partially or complete obstruct the
pipeline.
[0017] FIG. 1 shows a system 10 for high intensity ultrasound in
pipeline obstruction remediation. The system 10 includes an
ablation transducer 12, a detection transducer 14, a transmit
beamformer 16, a receive beamformer 18, a processor 20, and a
memory 22. Additional, different, or fewer components may be used.
For example, the ablation and detection transducers 12, 14 may be a
same device. As another example, more transducers of either type
may be provided. In another example, a display is provided.
Different transmit beamformers 16 may be used for the different
types of transducers 12, 14. In yet another example for remediation
relying on other types of detection, the receive beamformer 18 and
detection transducers 14 are not provided.
[0018] In one embodiment, the system 10 is part of a fixed
installation. The system 10 is positioned, at least partly, around
a pipeline at one location. Using straps, bolts, glue, clamps, or
other connector, the system is fit to, held around, or connected
with the pipeline. In another embodiment, the system 10 releasably
connects with the pipeline or is part of a robot for moving along
the pipeline. The system may be pulled along the pipeline
manually.
[0019] The components of the system 10 are in a same housing. For
an undersea or other deployment, a cable for communications and
power is provided to the components of the system 10. Rather than
transmitting beamforming or other ultrasound data path signals,
control signals and power are transmitted over a long cable or
wirelessly. An image may be transmitted. Alternatively, or
additionally, a binary signal indicating detection of an
obstruction or not is transmitted. In one example deployment, a
boat or rig with a power source permanently or releasably connects
with a cable supported by a buoy for operating the system 10. In
alternative embodiments, one or more components are in a separate
housing. For example, the processor 20 and memory 22 are with the
power source and connect to the beamformers 16, 18 and transducers
12, 14 through a cable.
[0020] The ablation transducer 12 is any now known or later
developed transducer for generating high intensity ultrasound from
electrical energy. A single element may be provided. The single
element may have a focus due to shape or a lens or may be
unfocused. A plurality of elements in a one or multi-dimensional
array may be used, such as an array of N.times.M elements where
both N and M are greater than one for electric based focusing or
steering.
[0021] The element or elements are piezoelectric,
microelectromechanical, or other transducer for converting
electrical energy to acoustic energy. For example, the ablation
transducer 12 is a capacitive membrane ultrasound transducer.
[0022] The ablation transducer 12 is operable from outside the
pipeline. For example, the ablation transducer 12 is a probe or
other device held against the exterior of the pipeline or
surrounding insulation. The emitting surface of the ablation
transducer 12 is curved to fit on the pipeline. Different amounts
of curvature are used for different pipeline sizes. Alternatively,
a matching block or other piece fits between the ablation
transducer 12 and the pipeline. In one embodiment, pipe insulation
is applied over the ablation transducer 12 so that the ablation
transducer contacts the pipeline or a matching layer substance on
the pipeline. The ablation transducer 12 is handheld, positioned by
a device, strapped or otherwise placed into contact with the
pipeline. In other embodiments, the ablation transducer 12 is in a
pig, probe, or other device for operation from within the
pipeline.
[0023] In one embodiment, only one ablation transducer 12 is
provided. In other embodiments, a plurality of ablation transducers
12 is provided. For example, a plurality of two-dimensional arrays
of elements is used for transmitting from different locations to an
ablation or remediation region. FIGS. 2 and 3 show use with a
plurality of ablation transducers 12.
[0024] The detection transducer 14 is the same or different type,
material, size, shape, and structure than the ablation transducer
12. For example, one or more detection transducers 14 each include
a multi-dimensional array of capacitive membrane ultrasound
transducer elements. The detection transducer 14 is any now known
or later developed transducer for diagnostic ultrasound imaging or
detection. The detection transducer 14 is operable to transmit and
receive acoustic energy.
[0025] Where the detection and ablation transducers 12 14 are
different devices, the spatial relationship between the transducers
12, 14 is measurable. For example, pairs of the detection and
ablation transducers 12, 14 are fixedly connected together or a
sensor measures the relative motion between the two. Any sensor may
be used, such as magnetic position sensors, strain gauges, fiber
optics, or other sensor. Alternatively or additionally, acoustic
response from the arrays indicates the relative positions.
Correlation of imaging data may indicate spatial relationship
between detection transducers 14. In other embodiments, the same
array or arrays are used for both remediation and imaging.
[0026] In one embodiment, the remediation and detection transducers
12, 14 are in a cuff 24. The cuff 24 is plastic, metal, fiberglass,
or other material for rigidly, semi-rigidly or flexibly holding the
plurality of transducers 12, 14 with or without the beamformers 16,
18, and/or processor 20. For example, FIG. 2 shows a cuff 24 with a
plurality of transducers 12, 14. Hinges, other structure, or an
outer casing interconnect the transducers 12, 14. One or more sets
of transducers may be more rigidly connected.
[0027] The cuff 24 includes every other transducer as a detection
transducer 14 and an ablation transducer 12. Other ratios and/or
arrangements may be provided. One, more, or all of the transducers
may be dual use devices, such as each transducer 12, 14 being for
detection and ablation. In one embodiment, each of the detection
transducers 14 is operable to electronically or electronically and
mechanically scan in three dimensions for acquiring data
representing a volume. The transducers 14 may be arranged such
that, at least for deeper depths within the pipeline, the scan
volumes of adjacent detection transducers 14 overlap. In
alternative embodiments, the detection transducers 14 scan along a
plane or line. The detection transducer(s) 14 may be used to merely
detect the presence or not of an obstruction, so may have no or a
fixed focus and scan only in one direction.
[0028] A covering, such as a fabric, plastic or other material, may
relatively connect the transducers 12, 14. A housing encapsulates
the cuff 24, waterproofing the system 10. For example, the
transducers 12, 14, transmit beamformers 16, 18, processor 20, and
memory 22 are enclosed within the covering. The cuff 24 is a band
or other structure for wrapping around, connecting to, or resting
on the pipeline. FIG. 2 shows the cuff 24 of transducers 12, 14
wrapped at least partially around a pipeline with some internal
flow region represented. The ultrasound devices are embedded in a
flexible surface, wrapped around the pipeline. This geometry may
allow acquiring 360-degree images around an obstruction with a
single array.
[0029] In one embodiment, the transducers 12, 14 are distributed in
a blanket type arrangement or multi-dimensionally. FIG. 2 shows the
transducers 12, 14 in a linear arrangement wrapped at least
partially around the pipeline. FIG. 3 shows the transducers 12, 14
wrapped entirely around the pipeline 26. Additional of these
arrangements may be placed adjacent to each other in the same or
different cover to blanket the pipeline so that multiple
transducers 12, 14 are provided along a length direction of the
pipeline.
[0030] The cuff 24 connects to or around the pipeline. For example,
magnets connect the cuff 24 to the pipeline. As another example, a
strap or pipe clamp holds the cuff 24 to the pipeline. Glue or
other fasteners may be used.
[0031] The cuff 24 adapts to the pipe orientation. By wrapping the
cuff 24 at least partly around the pipeline, the flexible or hinged
portions of the cuff 24 adapt the cuff 24 to the pipe. One size
cuff 24 may be used on different sized pipes or cuffs 24 for
particular sizes of pipes are used. The width of the cuff 24 (i.e.,
distance along the length of the pipe) is sized as appropriate for
the plug, pipeline, or comprehensive remediation approach.
[0032] The transmit beamformer 16 has a plurality of waveform
generators, pulsers, amplifiers, delays, phase rotators, and/or
other components. For example, the transmit beamformer 16 is
waveform generators for generating square or sinusoidal waves in
each of a plurality of channels. The waveform generators or
downstream amplifiers set the amplitude of the electrical
waveforms. For detection, the amplitude is set to provide scanning
with one or more acoustic beams. The amplitude may be set for the
same for scanning to detect and for high intensity ultrasound to
ablate. Alternatively, the scanning for detection uses a lower
amplitude to limit reverberation associated with sound reflections
within the pipe.
[0033] Relative delays and/or phasing of the waveforms focus the
transmitted acoustic energy. By applying relatively delayed and/or
apodized waveforms to different elements of a transducer, a beam of
acoustic energy may be formed with one or more foci along a scan
line. Multiple beams may be formed at a same time. For electronic
steering, the relative delays establish the scan line position and
angle relative to the transducer 12, 14. The origin of the scan
line on the transducer 12, 14 is fixed or may be adjusted by
electronic steering. For example, the origin may be positioned on
different locations on a multi-dimensional array. The different
origins result in different positions of the respective scan
lines.
[0034] In an alternative embodiment, fixed focus or no focus is
provided. The element or elements of the transducer generate a
wavefront without steering by the beamformer 16. The detection
transducers 14 may use electronic steering, and the ablation
transducers 12 may not, or vice versa. The transmit beamformer 16
may generate electrical waveforms for generating acoustic energy,
whether steered or not.
[0035] For ablation or remediation, relatively delayed electrical
signals are generated by the transmit beamformer 16 for focusing
the high intensity focused ultrasound at a portion of the pipeline
obstruction spaced from walls of the pipeline. FIG. 3 shows the
beams 26 from multiple transducers 12 focused at the center. The
portion may be determined from a known size of the pipe. The focus
is positioned to be at a center or other location of the pipe.
Alternatively, the potion is determined from image analysis of an
ultrasound imaging of the pipe. In other embodiment, the beams 26
are not focused, but the transducers 12 are pointed so that the
acoustic energy from the different beams 26 constructively
converges at the center or near the center.
[0036] For scanning or detection, focused or unfocused
transmissions are generated by the transmit beamformer 16. For
example, a fixed or no focus is used to detect response from a
given location, such as the center of the pipe. As another example,
beams are formed along different scan lines. Any pattern may be
used, such as linear, sector, or Vector.RTM.. The pattern is for
scanning a plane. A volume may be scanned by a scan format for the
volume or by scanning multiple planes.
[0037] The receive beamformer 18 receives electrical signals from
the detection transducer 14. The electrical signals are from
different elements transducing from acoustic echoes from the
transmission. Using delay and sum beamforming, fast Fourier
transform processing, or another process, data representing
different spatial locations in a volume is formed. One, a few, or
many transmission and reception events may be used to scan a volume
with the detection transducer 14. For example, plane wave
transmission and reception is used for scanning a volume. Multiple
beam reception with or without synthetic beam interpolation speeds
volume scanning with delay and sum beamformation. In alternative
embodiments, a two-dimensional plane or scan lines are scanned
instead of a three-dimensional volume. In yet another alternative
embodiment, the receive beamformer 18 samples along a single line
or for a single location, such as associated with measuring flow at
a center of the pipeline.
[0038] The beamformed data is detected. For example, B-mode
detection is provided. In another example, Doppler power, velocity,
and/or variance are detected. Any now known or later developed
detection may be used. The detected data may be processed to
determine volume flow, pressure, or other information, such as by
processing combinations of different types of detected data (e.g.,
B-mode to determine area of flow and Doppler velocity to determine
rate of flow for deriving volume flow). The detected data may be
scan converted, remain formatted in the scan format (e.g., polar
coordinate), interpolated to a three-dimensional grid, combinations
thereof, or converted to another format. In another embodiment, the
detection represents a single point or imaging is not being
provided, so scan conversion is not provided. The detection and/or
format conversion are done by separate devices, but may be
implemented by the processor 20.
[0039] The processor 20 is a general processor, central processing
unit, control processor, graphics processor, digital signal
processor, three-dimensional rendering processor, image processor,
application specific integrated circuit, field programmable gate
array, digital circuit, analog circuit, combinations thereof, or
other now known or later developed device for detection of an
obstruction and/or controlling application of high intensity
ultrasound in remediation. The processor 26 is a single device or
multiple devices operating in serial, parallel, or separately. The
processor 26 may be a main processor of a computer, such as a
laptop or desktop computer, or may be a processor for handling some
tasks in a larger system, such as in an imaging system. The
processor 26 is configured by hardware and/or software.
[0040] The processor 20 identifies the pipeline obstruction with
the detection transducer 14. One or more detection transducers 14
are used by the beamformers 16, 18 under the control of the
processor 20. The processor 20 identifies any obstruction from the
beamformed data. The data representing a point, line, plane, or
volume may be processed to identify the obstruction. The speckle
characteristic from B-mode data may indicate the type of material
(e.g., oil verses wax). The shape or arrangement may indicate an
obstruction, such as showing a channel or other region different
than elsewhere within the pipe (i.e., other than smooth cylinder).
The amount of flow may indicate an obstruction. If no or unusually
rapid or turbulent (variance) flow is detected, an obstruction may
be indentified.
[0041] The obstruction is identified as being generally within the
pipe. Alternatively, the location of the obstruction along a length
of the pipe is identified. For example, the scan may include
regions of the pipe directly next to or between the transducers 14,
next to or between one and not others of spaced apart detection
transducers 14, or upstream or downstream of the detection
transducers 14.
[0042] The processor 20 causes the transmit beamformer 16, with at
least one ablation transducer 16, to transmit the high intensity
ultrasound from the ablation transducer(s) 16 and at the
obstruction. The processor 20 may control the focus of the
generated beams 26. A sequence, repetition rate, duration, focal
scan pattern, amplitude, frequency or other characteristic of the
beams 26 may be controlled. For example, different beams 26 are
used for different types of plugs or size of plugs or different
size of pipes (e.g., more power for larger pipes and associated
plugs). As another example, the beams 26 vary based on the amount
of flow created or not. In another embodiment, the processor 20
merely controls whether the transmit beams 26 are turned on or not.
The beams 26 are fixed (i.e., same frequency, focus, and/or
amplitude) and the processor 20 turns on these fixed beams 26 when
an obstruction is detected.
[0043] The processor 20 controls the transmission for all of the
ablation transducers 12. The ablation transducers 12 may be
operated the same, such as having a same frequency, amplitude,
and/or focus relative to the transducers 12. The transmit
beamformer 16 may be controlled to provide for different foci for
the different transducers 12, such as for directing the beams all
to a same location within the pipe (i.e., different transducers 12
steer differently to project the beam to the same location). The
beams 26 may be directed to different locations, such as having
some beams 26 directed to an upstream location on the plug at a
center of the pipe and others to a downstream location on the plug
at the center of the pipe. The processor 20 may control the
transmit beamformer 16 to cause the beams to be formed along
particular paths or with different characteristics. Air pockets or
regions of greater density in the plug may be identified. The beams
may be formed to avoid intersecting these regions.
[0044] The processor 20, based on interleaved or later performed
scanning for detection, may determine an amount of remediation of
the obstruction. An amount of flow, velocity of flow, area of
opened channel or other characteristic of remediation may be
detected. By heating the plug with the high intensity ultrasound, a
channel may be opened and flow increased or started. The processor
20 may monitor progress in order to steer further transmissions,
cease remediation, and/or report.
[0045] The memory 22 stores the ultrasound data for detection
processing. Alternatively, or additionally, the memory 22 stores
instructions for programming the processor 20 for obstruction
remediation. The instructions for implementing the processes,
methods and/or techniques discussed above are provided on
non-transitory computer-readable storage media or memories, such as
a cache, buffer. RAM, removable media, hard drive or other computer
readable storage media. Computer readable storage media include
various types of volatile and nonvolatile storage media. The
functions, acts or tasks illustrated in the figures or described
herein are executed in response to one or more sets of instructions
stored in or on computer readable storage media. The functions,
acts or tasks are independent of the particular type of
instructions set, storage media, processor or processing strategy
and may be performed by software, hardware, integrated circuits,
firmware, micro code and the like, operating alone or in
combination. Likewise, processing strategies may include
multiprocessing, multitasking, parallel processing and the like. In
one embodiment, the instructions are stored on a removable media
device for reading by local or remote systems. In other
embodiments, the instructions are stored in a remote location for
transfer through a computer network or over telephone lines. In yet
other embodiments, the instructions are stored within a given
computer, CPU, GPU or system.
[0046] The system 10 may include a power source. The power source
may be local to the beamformers 16, 18, such as storage capacitors,
battery, water flow-based generator, or engine. In one embodiment,
the power source is remote, such as being on a boat or rig for
undersea pipelines. A small turbine or other source for outputting
kilowatts of power instantaneously or over time may be used.
[0047] FIG. 4 shows a method for high intensity ultrasound in
pipeline obstruction remediation. The method uses the system 10 of
FIG. 1, the cuff 24 of FIG. 2, the arrangement of FIG. 3, different
transducers, different arrangements, and/or different systems. The
acts are performed in the order shown or a different order.
Additional, different, or fewer acts may be used. For example, the
method is performed without act 28, act 30, and/or act 32. The
detection may be provided separately or the existence of the plug
assumed. For example, a pressure build-up may be detected in the
pipeline. Acoustic energy to remediate plugs is activated at one or
more selected locations along a length of the pipeline. In the case
of assuming there is a plug, the fluid and pipeline itself may
dissipate the heat without harm if no plug is at a given
location.
[0048] In act 28, the ultrasound transducers are positioned on the
pipe. A person may position the transducers, such as wrapping a
cuff or blanket around the pipe. The cuff or blanket may be
tightened or strapped to the pipe. A robot may position the
ultrasound transducers, such as a submersible robot placing the
transducers on the pipe. Using clamping, bonding, magnetism,
gravity, or other connection, the transducers are placed on the
pipe.
[0049] Prior to positioning on the pipe, a mating material may be
placed on the pipe or transducers. For example, ice is formed on
the pipe. As another example, an acrylic or mercury is deposited on
the pipe or transducers. The mating material has an acoustic
impedance between the acoustic impedance of the transducers and the
pipe. Layers of different material may be used, such as to provide
a more gradual transition of acoustic impedance. These matching
layers may avoid more sudden transitions in acoustic impedance,
allowing transmission of more acoustic energy into the pipe.
[0050] The transducers are spaced around a portion of the pipe. For
example, the transducers are spaced around at least 120, 150, or
180 degrees of the circumference of the pipe. The transducers may
be spaced around the entire circumference of the pipe. The
transducers may have no or some spacing between each transducer.
FIG. 2 shows transducers with little spacing, but with ablation
transducers spaced apart by detection transducers. FIG. 3 shows the
ablation transducers spaced apart, with or without any intervening
transducers. Alternatively, a single transducer (e.g., element or
array) is positioned at one location on the pipe.
[0051] The transducers may also be spaced along a length of the
pipe, such as positioning a multi-dimensional array of transducers
where each transducer is a single element, one-dimensional array of
elements, or multi-dimensional array of elements. Any spacing may
be used between transducers along the length of the pipeline. Any
pattern of distribution of the transducers along and around the
pipeline may be used.
[0052] In act 30, the pipeline is scanned with ultrasound. The
scanning may be merely transmitting and receiving at a given
location. Alternatively, the scanning is steering transmit and
receive beams over a plurality of spaced apart scan lines. Acoustic
energy is transmitted along a plurality of scan lines, and echoes
are received in response to the transmissions. The received echoes
are converted into received electrical signals. The transmission
and reception are performed for imaging and/or detecting
obstruction. A point, line, plane, or volume is scanned.
[0053] One or more transducers are used for detection. The scanning
is performed with a single array or transducer or with different
transducer arrays of elements. For example, one or more transducers
scan the same or different lines or points for detection without
combination. In another example, different transducers scan the
same region or overlapping regions in the pipe (e.g., scan
overlapping or a same cross-section of the entire or central
interior of the pipe). The resulting data from the different
transducers may be aligned and combined.
[0054] Rather than line, point, or plane scanning, a dataset
representing a three-dimensional volume may be formed by
transmitting and receiving. The dataset is formed by scanning an
entire volume. Alternatively, different scans of overlapping
volumes are performed, and the overlapping volumes are combined.
Different transducers scan different, but overlapping volumes.
[0055] In one embodiment, a stitching or "mosaicking" operation
combines different volumetric datasets. For example, a first volume
is expanded or added to with each new volumetric acquisition, while
assuring insertion of the new information at the correct spatial
position. In one embodiment, an ultrasound blanket device performs
an initial acquisition, taken as reference. Then, additional
volumes are sequentially acquired for combination.
[0056] The overlapping volumes are aligned. Position sensors, data
correlation, or combinations thereof are used to determine the
relative spatial position of the overlapping volumes. For
correlation, speckle or features may be used. In one embodiment,
power Doppler information is segmented to identify one or more
surfaces in each data set. The surfaces are then correlated by
searching different rotations and/or translations. The relative
position with the highest or sufficient correlation indicates the
proper alignment. Cross-correlation, minimum sum of absolute
differences, or other correlation may be used.
[0057] In other embodiments. B-mode data is used for alignment. In
another embodiment, the power Doppler-based alignment is refined by
further B-mode alignment. The power Doppler provides a lower
resolution alignment, and the B-mode provides a higher resolution
alignment. Features, speckle, segmentation, or other processes are
used for B-mode alignment. For example, B-mode data with or without
spatial filtering is correlated without specific feature
extraction. In yet another embodiment, position sensor information
or known spatial limitations of the relative position of the
transducers (e.g., semi-rigid connection between transducers) is
used to limit the search space for correlation. Any search
technique may be used, such as set searching, numerical
optimization, coarse-fine, or other.
[0058] The data of the aligned volumes is combined. The information
is merged with the previous scan, based on the known mutual
location of the transducers or volumes. Any combination may be
used, such as selecting a datum for each spatial location from
available datasets, averaging, weighted averaging to avoid
combination artifacts, or interpolation. The aligned and combined
volumes provide a larger three-dimensional volume. The volume
dataset may be used for three-dimensional position determination.
For example, a cut plane, which intersects and is co-axial with a
plug, is formed for identifying a region to be ablated.
[0059] The scanning is performed with different transducers than
used for remediation. Alternatively, the same transducers are used
for both detection and remediation.
[0060] In act 32, the obstruction is detected from the scanning.
Any detection may be used. For example, flow in the pipeline is
measured. Any technique for measuring flow in a pipe may be used.
The velocity at one or more locations (e.g., velocity throughout an
area of a cross-section) is measured. The power of the flow return
or the variance may alternatively or additional be used. The
spectrum of flow at one or more locations may be measured, such as
using spectral Doppler techniques. A higher than normal velocity
may indicate a partial blockage. No or little flow may indicate a
complete blockage. The flow may be detected at one location or a
plurality of locations.
[0061] In another embodiment, morphology of the obstruction is
identified. A characteristic of the acoustic return from a plug may
be different than from the gas, oil, or other flowing contents of
the pipe. Using frequency, amplitude, speckle, or other analysis,
the characteristics associated with a plug may be detected. For
example, a wall or surface within the pipe may be detected. As
there should be no surface other than from a plug, the plug is
detected. Data representing a volume may be analyzed to find the
continuous surface or surfaces of the plug, such as a front and
back wall with or without any flow channels of the plug. The
locations of the obstruction are detected.
[0062] The obstruction in the pipe is detected with ultrasound
transmitting and receiving from outside of the pipe. Alternatively,
the obstruction is detected with a pig using ultrasound, optics or
other mechanism. In other embodiments, the plug is not
detected.
[0063] Based on the detection and/or scanning, the portion of the
plug or within the pipe to be ablated or removed is identified. The
region to be remediated is identified. Manual, automatic, or
semi-automatic identification is used. For example, the user
selects a point in different views as indicating the location at
which a channel is to be formed. The geometric relationship of the
different views may provide an indication of a location in a
volume. As another example, a processor identifies the region. An
image process is performed to identify the shortest channel that
may be formed whether at the center or not. The volume dataset or
other data representing the plug is processed.
[0064] In one embodiment, ultrasound data representing the volume,
such as acquired with a blanket ultrasound device, is used to
localize a weak point in the plug. For example, a line associated
with a shortest distance between upstream and downstream walls of
the plug is found. As another example, B-mode data shows material
of the plug more likely to respond to high intensity ultrasound. In
yet another example, acoustic force radiation is used to vibrate
the plug to identify weaknesses, such as more or less rigid regions
of the plug.
[0065] In an alternative embodiment, a specific region of the plug
is not identified. Instead, the portion for remediation is assumed,
such as using a center of the pipe along a length regardless of a
length of the plug or based on a length of the plug.
[0066] Based on the selected region, detected type or material of
the plug, size of the plug, diameter of the pipe, thickness of the
pipe, type of material of the pipe, temperature, pressure, or other
characteristic, the characteristics of the high intensity
ultrasound transmit beam or beams are determined by a processor, by
a user, or combinations thereof. The characteristics include power,
frequency, and/or other characteristics (e.g., duration, sequence,
or pulse repetition interval). The determination may be a function
of the selected region to be ablated. The determination is a
function of the desired ablation or amount of power to be delivered
in a specific period to cause destruction, melting, disintegration,
or reincorporation. Any now known or later developed dosage
considerations may be used.
[0067] In one embodiment, the power and frequency of the high
intensity ultrasound is determined, at least in part, as a function
of a characteristic of the path from the transducer to the location
of ablation. For example, the frequency of the high intensity
ultrasound adapts as a function of depth from the transducer,
attenuation characteristic along the path, or combinations thereof.
The optimum frequency depends on the target depth, attenuation
constant, the transmit transfer function of the transducer, and any
limiting factor, such as the loss of acoustic energy passing
through the pipe. Limiting factors may include, for example,
maximizing the power absorption at the target depth or minimizing
the power absorption at or near the pipe. The frequency at which
the acoustic intensity is highest may not be the optimum frequency
because of the frequency dependence of the acoustic absorption. A
desired or optimum frequency may be calculated given the target
depth, pipe thickness, pipe material, and the type of plug material
between the target and the transducer. Image processing,
thresholding, a predetermined setting, or other technique may be
used to distinguish types of material. The different types are
associated with different acoustic attenuation.
[0068] Heating is achieved by absorption of acoustic power.
Acoustic absorption is proportional to an attenuation coefficient.
Higher attenuation provides higher acoustic power absorption and
heat generation. Attenuation and absorption increase with
frequency, so it is desirable to use higher frequencies for
heating. However, higher propagation attenuation at higher
frequencies means shallower penetration depth. There is a trade-off
between penetration depth and frequency, and heat. For a given
depth of the treatment region, there may be a better frequency at
which maximum power deposition (so .DELTA.T) is achieved.
[0069] For a plane wave, the pressure at a depth z is related to
the pressure at the surface of the transducer with the following
equation:
P(z)=P.sub.0e.sup.-.alpha.f.sup.k.sup.z,
[0070] P(z) is the pressure amplitude as a function of depth (z),
P.sub.0 is the pressure at z=0, and .alpha.f.sup.k is the frequency
dependent tissue attenuation constant (k usually takes a value
between 1 and 2 depending on the material). The acoustic power
absorbed by the material, L(z), is then calculated as:
L ( z ) = .alpha. f k Z 0 P 2 ( z ) ##EQU00001##
Absorbed power is proportional to the frequency dependent
attenuation constant. The frequency where maximum acoustic power
absorption is achieved:
f max = ( 1 2 .alpha. z ) 1 k ##EQU00002##
The optimum frequency depends on the depth and attenuation
constant. Note that, this calculation is for simple plane waves and
is intended to show the dependence of the optimum frequency on the
depth and attenuation constant. Ablation beams may be transmitted
as a plane wave, with no focus, or with a greater focus. For a
transducer with transmit beamforming and a non-uniform material
type between the transducer and the target (e.g., non-uniform
attenuation constant), the optimum frequency may be calculated
numerically.
[0071] The absorption depends on the attenuation constant. Knowing
an average material attenuation or the material attenuation profile
between the target and the transducer may increase the accuracy of
optimum frequency calculation. The attenuation constant of
different detectable material types may be determined and
incorporated into the algorithm.
[0072] The operating frequency may be chosen to avoid heating the
pipe more than the target region of the plug. Depending on the
limiting factor (power absorption at the target depth or power
absorption at the pipe), the optimum frequency and/or amplitude may
be different. By spacing a plurality of transducers around the
pipe, greater heating is likely within the plug than at any point
on the pipe.
[0073] In addition or as an alternative, the power dose of the high
intensity ultrasound from each of the transducers is determined.
The power dose may be determined a function of material along the
beam path, distance from the transducer to the treatment region
along the path, number of paths, frequency of the transmission,
combinations thereof, or other factors. For example, different
material types provide different attenuation. The different
attenuation of the treatment region and the regions between the
treatment region and the transducer may alter the power delivered
for treatment. Greater attenuation along the path may result in a
higher power dose transmitted from the transducer. Greater
absorption at the treatment region may result in a less power dose
transmitted from the transducer. The reflections of acoustic energy
within the pipe may be considered. The power dose is altered by
changing frequency, amplitude, or number of cycles of the
transmitted waveforms.
[0074] The specific material type may be identified. Alternatively,
the intensity of the echoes or data along the path may indicate
material characteristics. By collecting the intensities along the
paths, the amount of power to reach that particular point of
ablation with a desired power level is calculated. The average
intensity, sum of intensities, or intensity profile may correlate
with attenuation. Other functions may be used to determine power
dose.
[0075] In an alternative embodiment, plug and/or pipe
considerations are not calculated. Instead, an assumed or standard
power dose is used.
[0076] In act 34, acoustic energy is transmitted into the pipeline.
The acoustic energy is transmitted as one or more beams focused at
a same region at a same time. The beams are focused by
corresponding arrays of elements. Using delays and/or apodization,
the elements of each array generate acoustic energy that
constructively interferes at the focus. Alternatively, the acoustic
energy is transmitted without focus but from different directions
so that the region of greatest intensity is away from the walls of
the pipe. With or without focused beams, the acoustic energy from a
plurality of ultrasound transducers positioned around at least a
portion of the pipeline contribute to energy at a region of the
plug. Alternatively, acoustic energy from a single transducer is
used.
[0077] The transmission is in response to the detection of the
plug. Once the plug is detected, the transmissions begin
immediately. The transmissions may instead delay a start until a
control signal, such as from a user or timer, is received.
[0078] The acoustic energy is transmitted from outside of the
pipeline. The transducers are positioned around the pipeline at
various locations, such as shown in FIG. 3. The acoustic energy
from the locations travels through the pipe walls and into the
pipe, such as into the plug. Given the transducer spacing around at
least a part of the periphery of the pipe, the beams of acoustic
energy converge at a desired region of the plug, such as at a
center of the pipe or other region.
[0079] The acoustic energy at the convergence has the power to melt
or remediate the plug. The transmissions are of a desired power or
power profile over time and frequency or frequency profile over
time to remove the plug material at the region of convergence. The
frequency may be any acoustic frequency, such as greater than 1 MHz
or 20-400 kHz. The power dose may take into consideration the
reflection of acoustic energy from the pipe walls. Energy
propagating into the pipe may bounce off of an opposite wall. For
example, reflection at the steel/ hydrate interface leads to most
of the energy being dissipated in the hydrate. The frequency,
amplitude, sequence of transmissions, duration, and pulse
repetition interval may be set based on the pipe material, plug
material, and any environment factors (e.g., temperature and
pressure).
[0080] In act 36, the transmissions of the acoustic energy are
directed to a portion of the obstruction. The portion is away from
walls of the pipeline. By directing the transmissions, a greater
intensity of the acoustic energy is provided at the portion than
locations spaced away from the portion. The acoustic energy focused
from one array, provided from the different arrays, and/or due to
reflections from the pipe constructively sums at the portion and
less so at the plug near the walls of the pipe.
[0081] In one embodiment, the locations of the transducers, with or
without focus of the beams, direct the acoustic energy to the
center or other location. For example, FIG. 3 shows the beams 36
constructively summing at the center. Similarly, reflections may
cause greater intensity at the center or other non-wall
location.
[0082] In another embodiment, the beams are focused. Using a single
transducer or a group of transducers, the beam or beams are
directed to the desired location, such as the center of the pipe.
The detected location of the plug is used to guide focus of the
beams. A weak point or other detected information about the plug
may be used to guide the focus of the beams.
[0083] The location of the focus or portion being subjected to the
greatest or most of the acoustic energy may shift over time. As the
plug material is removed, the focus may shift to continue to remove
other material. The acoustic energy is focused on one section at a
time. Other sections remain cool, heat less, or are remediated
less.
[0084] The focal points of the various beams may be formed at other
locations, such as at a different point or along a line. Different
arrays or different beams from the same arrays may be directed to
different portions of the plug in an interleaved or simultaneous
manner. A channel or larger region may be remediated at a same
time.
[0085] In one embodiment, the ultrasound remediation is combined
with other remediation. For example, a warming blanket or other
source of external heat is applied to the unpressured end of the
plug. The plug is melted by this external heat. When only a certain
amount, such as 1-2 feet of plug material completely blocking the
pipe remains, ultrasound is used to open a channel. The ultrasound
may be used to grow the channel to a larger diameter, such as up to
the internal wall of the pipe. External heating may be used for
further removing any remaining plug deposits at the wall of the
pipe. As another example, ultrasound is used to open a channel.
Once open, flow will begin. A chemical may be inserted into the
pipe and flow to the remaining blockage. The chemical may assist or
complete removal of the plug material.
[0086] In act 38, an aperture is opened in the obstruction. The
acoustic energy causes an opening for form. In one embodiment, the
acoustic energy causes heat. The heat melts the plug material. In
other embodiments, the acoustic energy causes cavitations or bubble
formation in the plug. This acts to destroy the structural
integrity of the plug. In yet another approach, the acoustic energy
causes displacement of plug materials by the passing acoustic
waves. This vibration may weaken or remove plug material.
Combinations of heat, cavitations, and/or displacement may be
used.
[0087] One portion of the plug is remediated (e.g., heated) by the
acoustic energy more than another portion. For example, the center
is heated more than the parts adjacent to the pipe. The acoustic
energy travels from different directions to constructively combine
at the desired portion with less constructive combination adjacent
to the pipeline. The plug is gently melted from the inside out in
cross-section and/or in length along the pipe using conformal high
intensity ultrasound.
[0088] As the acoustic energy propagates into the plug material,
the acoustic waves may be absorbed and converted to heat.
Absorption of sound by hydrate or plug material is much higher than
steel or pipe material, allowing remediation of the plug material
without heating the pipe as much.
[0089] As the plug is remediated, the blockage material
progressively reincorporates into the flow stream. Once a channel
is formed, the flow will increase, but without creating a ballistic
object out of the plug. The opening may decrease the pressure,
returning the pipeline to safer operation.
[0090] The transmission and directing acts 34, 36 are repeated. The
repetition is performed to form a channel in the plug or remove the
plug. The repetition may alternatively or additionally be performed
to complete remediation at a given point. The scanning and
detection may be repeated, such as repeating to monitor progress of
the remediation. The characteristics of the beams, the locations,
the pulse repetition frequency, and/or the duration may be altered
based on imaging feedback. The focal region may be altered based on
feedback. Alternatively, the beams and/or focus remain the same
until the plug is no longer detected or a time limit is
reached.
[0091] While the invention has been described above by reference to
various embodiments, it should be understood that many changes and
modifications can be made without departing from the scope of the
invention. It is therefore intended that the foregoing detailed
description be regarded as illustrative rather than limiting, and
that it be understood that it is the following claims, including
all equivalents, that are intended to define the spirit and scope
of this invention.
* * * * *